Traffic protection apparatus



June 26, 1951 H. G. WITMER TRAFFIC PROTECTION APPARATUS Filed April 22, 1946 [dm n d MMR@ .@fw mdlmeom s? 5m? w n A TLIT am. m @www PMPMIG do 5F@ M000 w .A (ii MIM 0 1 w IJ; gli, M a g 2 www@ B Z w 2 m N N 90; M l b@ \I--L\ x EBF ,f DH

by current controlled by contact II of relay R. Alternating current of low frequency is therefore generated in secondary winding d of transformer F, and is rectied by contact 2I of relay R. The current thus rectified energizes a code detecting relay RP which controls signals for governing traflic movements over tracks IT and, 2T.

Referring now to Fig. 2, the'apparatus here shown dilfers from that of Fig. l in that the current supplied to the track circuits is controlled by polar contacts 25 and 26 of relay R instead of by contacts of a separate coding device CT; and relay R is made slow acting by some suitable means such, for example, as electrolytic condensers 21 and 28 connected in multiple with the relay windings 9 and I2, respectively. In this arrangement, relay R therefore serves as the code transmitter for coding the current suppliedto the track circuits.

Having described, in general, the arrangement and operation' of the apparatus, I shall now describev its operation more in detail. 4

As shown in the drawings, all parts are in the normal condition, that is, switches IW and 2W are in their normal position; crossover track 3T is unoccupied; coding'device C'Iis constantly energized, and its contacts 5 and I6 are therefore tion w-b, winding 9 becomes shunted, causing winding V9 to be deenergized. Under either of these conditions, contacts I'I and 2I of relay R will be operated to their left-hand position in response to energization of winding I2, and will remain in that position until Winding 9 again bebeing repeatedly operated between their front and back points as shown in the drawings; windings 9 and I2 of relay R are being energized alternately; transformer F and relay RP are, in turn, energized; and contacts 23 and 24 of relay RP are closed in signal control circuits for tracks IT vand 2T.

In the apparatus shown in Fig. 1, each time when contact 5 closes at its front point, a circuit is closed for energizing winding 9 of relay R, this circuit passing from the positive terminal of battery IQ, through the front point of contact 5 of coding device CT, variable resistor 6, rail 3h of track section ct-b, contactV I of switch IW closed in its normal position, variable resistor 8, winding 9 of relay R, contact Il! of switch IW closed in the normal position, and rail 3a of section' a-b back to battery IQ. Each time when contact J6.. closes at itsback. point, a circuit is closed for energizing winding I2 of relay R, this circuit passing from the positive terminal of battery 2Q, through rail 3b of section b-c, contact II of switch 2W closed in the normal position, winding I2 of relay R, variable resistor I3, contact I4 of switch 2W closed in the normal position, rail 3a of section b-c, variable resistor I5,

and contact I6 of coding device CT back to battery 2Q.

Each time when winding 9 is energized, relay Rmoves its contacts I1 and 2l to the right-hand position, and each time when winding I2 is energized, relay Rmoves its contacts II and 2l to the left-hand position in which they are shown When contact I'I is closed inA in the drawings. the left-hand position, a circuit is closed for energizing portion I8 of vprimary winding m of transformer F, this circuit passing from terminal B, through contact I'I of relay R closed in the left-'hand position, and portion IS of winding m to terminal N. When contact I'I is closed in the from. that. in which-portion-I-S has been energized l The positioning of the -polarcontacts' of 'f relay'n comes energized after the train leaves section w-lb and switch IW is restored to its normal position. l

f Similarly, if switch 2W is moved away from its normal position or if a train enters section b-c, winding I2 of relay R Will become deenergized. In either of these instances, contacts I'I and 2I will be operated to their right-hand position in response to energization of winding 9, and will remain in that position'until winding I2 again becomes energized.

If both windings 9 and I2 should become de- ;energized, contacts I'I and-2| will remain in the position to which they were last previously operated, until one or bothof windings 9 and I2l shall again become energized.

'When contact Il remains continuously in one position or the other, only one of the portions I8 and I9' of primary winding m of transformerfF will be energized, so that-:winding m will be energized by current flowing in only one direction; f Under this condition, no current will be generated iin secondary winding d of transformer F, andhence relay RP will be deenergized and its conltacts 23 and 24 will beopened, causing signals for tracks IT and 2T to indicate stop.

In the modification of the apparatus shown 'Lin Fig. 2, with contact 25 of relay R closed in the left-hand position as shown in the drawing,

a circuit is completed for energizing winding 9 of relay R, this circuit passing from the positive terminal of battery IQ, through contact 25ofy relay R closed in the left-hand position, rail 3a of section ab, contact I0 of Switch IW closed in the normal position, variable resistor 8, winding 9 of relay R in multiple with condenser 21,

contact Iof switch IW closed in the normal posil tion, rail 3b of section ab, and variable resistor g 6 back to battery IQ. In response to energization of winding 9, relay R will operate its polar contacts I1, 2I, 25 and'26 to the right-hand position. l With contact 26 closed in the right-hand posi-Y tion, a circuit is completed for energizing winding I2 of relay R, this circuit passing from the positive terminal of battery 2Q, through variable resistor I5, rail 3a of section b-c, contact I4 of switch 2W closed inthe normal position, variable resistor I3, winding I2 of relay R in multiple l with condenser 28, contact II of switch 2W closed inthe normal position, rail 3b of section b-c, and

contact 26 vof relay R closed in the right-hand position, back to battery 2Q. In response to the energization of winding I2, relay R will operate itspolar contacts- I-'I,2I, 25 and 26 back to the left-hand position. Winding 9 will then again be-energized, and theoperations just traced will bef'repeated. Y Y

R in the eventl of deenergization of either or both of the windings 9 and I2 of relay R will be the same as already described for Fig. 1. The energization of transformer F and relay RP also occurs in the manner described for Fig. 1. y

Although I have herein shown and ydescribed only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a, stretch of railway track divided into two sections, a coding device having two contacts repeatedly operated at the same time alternately to a first position and a second position while said coding device is energized, means controlled by one of said contacts in its first position for supplying coded current to the rails of one of said sections, means controlled by the other of said contacts in its second position for supplying coded current to the rails of the other section, a polar stick relay having two control windings insulated from each other and one of which is connected across the rails of said one section and the other of which is connected across the rails of Said other section, two polar contacts each closed in a rst position by said polar stick relay in response to energization of said one winding and each closed in a second position by said polar stick relay in response to energization of said other winding, a decoding transformer, means controlled by one of said polar contacts for energizing the primary winding of said transformer alternately in opposite directions, means controlled by the other polar contact for rectifying the current output from the secondary winding of said transformer, and traffic governing means controlled by said rectified current.

2. In a crossover protection scheme in which a crossover track is divided into two sections, the combination comprising, means for supplying coded current to the rails of one of said sections alternately with the rails of the other section, a polar stick relay energized by current from the rails of one of said'sections rcontrolled by one of the track switches for said crossover track in its normal position and energized by current from the rails of the other section controlled by the other track switch for said crossover track in its normal position, two polar contacts each closed in a rst position by said polar stick relay in response to energization by current from the rails of said one section and each closed in a second position by said polar stick relay in response to energization by current from the rails of said other section, and traffic governing means con trolled by said polar contacts.

3. In combination, a stretch of railway track divided into two sections, means for supplying coded current to the rails of one of said sections alternately With the rails of the other section, a polar stick relay energized by current from the rails of one of said sections and alternately by current from the rails of the other section, two polar contacts each closed in a rst position by said polar stick relay in response to energization by current from the rails of said one section and each closed in a second position by said polar stick relay in response to energization by current from the rails of said other sec- 6 tion, and traffic governing means controlled by said polar contacts.

4. In combination, a stretch of railway track divided into two sections, a polar stick relay having a plurality of polar contacts operable simultaneously to a rst position in response to energization of said polar stick relay by current from the rails of one of said sections and also operable simultaneously to a second position in response to energization of said polar stick relay by current from the rails of the other section, means controlled by one of said contacts in its first position for supplying current to the rails of said other section, means controlled by another of said contacts in its second position for supplying current to the rails of said one section, and means controlled by said polar stick relay for controlling traflic governing means.

5. In combination, a stretch of railway track divided into two sections, a polar stick relay having a plurality of polar contacts operable simultaneously to a first position in response to energization of said polar stick relay by current from the rails of one of said sections and also operable simultaneously to a second position in response to energization of said polar stick relay by current from the Arails of the other section, means controlled by one of said contacts in its first position for supplying current to the rails of said other section, means controlled by another of said contacts in its second position for supplying current to the rails of said one section, and means controlled by other polar contacts of said polar stick relay for controlling trafc governing means.

6. In combination, a stretch of railway track divided into two sections, means for repeatedly supplying a pulse of current to the rails of one of said sections alternately with a pulse of current to the rails of the other of said sections, a polar stick relay having two windings one of which is controlled by energy received from said one section and the other of which is controlled by energy received from said other section in response to said pulses of current for operating polar contacts of said relay to a first or a second position respectively, and trafc governing means controlled by said relay.

'7. In combination, a stretch of railway track divided into two sections, means for repeatedly supplying a pulse of current to the rails of one of said sections alternately with a pulse of current to the rails of the other of said sections, a polar stick relay responsive to energy from said pulses received from said one section for closing polar contacts of said relay in a given position and responsive to energy from said pulses received from said other section for closing said polar contacts in the opposite position, and trafc governing means controlled by said polar contacts of said relay.

HAROLD G. WITMER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,356,553 Lay Oct. 26, 1920 1,816,302 Thompson July 28, 1931 2,017,546 OHagan Oct. 15, 1935; 2,039,820 McCann et al. May 5, 1936 2,213,186 Blosser Sept. 3, 1940 2,395,664 Ihrig Feb. 26, 1946, 

